Chose her ex...but it was a difficult decision. What should I do?

Toward the end of March I reached out to a girl through facebook who I had known 8 years previous (we had worked together). She had just gotten out of a 1 year relationship in January and was struggling. We spoke for about a month and a half over the phone with no physical contact. I knew that she was not over her ex then. In May we met and connected well. May through the end of July we had great times…too many to mention. We went canoeing, to visit her mother’s grave (her mother died when she was 6 yrs old) and to my grandmothers grave, on a trip to the beach, to a Mets game. We laughed, had fun, entered a committed relationship (she asked me, I didn’t ask her). We made love, and although there seemed to be intimacy issues I knew that she still occassionally thought about her ex…that hurt. Still I loved her deeply and felt with everything in me that she loved me. About 2 weeks ago she grew very distant. I told her that I often felt that she wasn’t present. She told me that she was in love with two people (me and her ex) and it hurt like hell. She pulled me close, then would push me away. She said she needed a few months to figure things out, then said she needed a few days. We both cried together, hugged, kissed…it was so difficult to leave her…from both sides, I believe. Now she is back with her ex…I am hurt, confused, and in shock. I know she loved me…I felt it. I am a 35yr old woman and I know what love feels like and what it doesn’t. She loved me. Now we have had no contact for 5 days and her ex spent this weekend at her house. I miss her every moment of the day. I am not sure if I will ever hear from her again and have no idea what to do. Please give any advice you can…thank you.